Nick Clegg today controversially scrapped Lib Dem proposals for an immigrant "amnesty" as he unveiled a tough new stance on visa abuse.

The deputy prime minister said plans to allow illegal immigrants to stay in the UK if they have been in the country for 10 years, which were seen as key to the party's manifesto in the run up to the 2010 general election, risked "undermining public confidence".

In his first speech on immigration as deputy prime minister, he said: "Despite the policy's aims, it was seen by many people as a reward for those who have broken the law."

He added: "That is why I am no longer convinced this specific policy should be retained in our manifesto for the next general election."

Taking a harder line on immigration, Clegg unveiled plans for bail-like security bonds, which would be paid as a cash guarantee from visa applicants coming from high-risk countries.

The bond plan has previously been sharply criticised by senior figures in the Lib Dems. In 2008 Simon Hughes said the idea was "clearly discriminatory".

"When will the government learn that what we need are sensible policies, not tough-sounding but half-baked ideas?" he said.

In an interview with The House magazine published today, business secretary Vince Cable also warned against turning on immigrants and criticised the Tory policy of placing a cap on migration.

"The reducing to under 100,000 is not government policy and it would be unattainable without, if it was attainable enormous damage would be done, notably through overseas students, which is one of the biggest components, actually," he said.

"We want to have lots of visitors from all over the world coming here without hassle, an easy flexible visa system, and we have lots of highly specialised people like engineers, top managers who we need in our companies and they’ve got to be able to come and go freely otherwise we are not going to be able to compete internationally. So I do have to keep banging the drum for that."

Clegg said he had spoken to both Cable and Hughes before delivering today's speech "at length".

He also said he "flatly rejected" the suggestion he had decided to tack to the right on immigration in order to see off the threat from Ukip.

Clegg said: "I have always believed if you want to have a society where people are tolerant towards each other ... one of the building blocks for that is that the public have confidence in how the [immigration[ system is run."